Synchronous memory device
First Claim
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1. A synchronous memory device comprising:
- a read command buffer providing a read signal in response to a read command;
a replica circuit providing a transfer signal whose time difference with respect to the feedback clock signal is substantially identical to a period that it takes the read command buffer to provide the read signal; and
a latency circuit receiving the read signal, and providing a latency signal having a predetermined time difference corresponding to a column access strobe (CAS) latency with respect to the read signal in response to the transfer signal.
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Abstract
A synchronous memory device, which includes a read command buffer, a replica circuit, and a latency circuit. The read command buffer provides a read signal in response to a read command. The replica circuit provides a transfer signal whose time difference with respect to the feedback clock signal is substantially identical to a period that it takes a read command buffer to provide the read signal. The latency circuit receives the read signal, and provides a latency signal having a difference of a predetermined time corresponding to CAS latency with respect to the read signal in response to the transfer signal.
13 Citations
12 Claims
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1. A synchronous memory device comprising:
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a read command buffer providing a read signal in response to a read command;
a replica circuit providing a transfer signal whose time difference with respect to the feedback clock signal is substantially identical to a period that it takes the read command buffer to provide the read signal; and
a latency circuit receiving the read signal, and providing a latency signal having a predetermined time difference corresponding to a column access strobe (CAS) latency with respect to the read signal in response to the transfer signal. - View Dependent Claims (2, 3)
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4. A synchronous memory device, comprising:
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a clock recovery circuit generating a data output clock signal in response to an external clock signal and a feedback clock signal;
a first replica circuit receiving the data output clock signal, providing a plurality of first transfer signals whose time differences with respect to the data output clock signal are shorter than a period that it takes a data output buffer to output data received from a memory cell array, and providing a feedback dock signal whose time difference with respect to the data output clock signal is substantially identical to a period that it takes the data output buffer to output data received from the memory cell array;
a second replica circuit receiving the feedback clock signal and providing a second transfer signal whose time difference with respect to the feedback clock signal is substantially identical to a period that a it takes a read command buffer to provide a read signal; and
a latency circuit receiving the read signal, and providing latency signals in response to the second transfer signal and the plurality of first transfer signals. - View Dependent Claims (5, 6, 7, 8)
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9. A synchronous memory device comprising:
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a clock recovery circuit generating a data output clock signal in response to an external clock signal and a feedback clock signal;
a first replica circuit receiving the data output clock signal and providing a feedback clock signal whose time difference with respect to the data output clock signal is substantially identical to a period that it takes a data output buffer to output data received from a memory cell array;
a clock delay circuit receiving the data output clock signal and providing first transfer signals having predetermined time differences with respect to the data output clock signal;
a second replica circuit receiving the feedback clock signal and providing a second transfer signal whose time difference with respect to the feedback clock signal is substantially identical to a period that it takes a read command buffer to provide a read signal; and
a latency circuit receiving the read signal and providing latency signals in response to the second transfer signal and the first transfer signals. - View Dependent Claims (10, 11, 12)
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Specification